# Compression Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

MinIO server allows streaming compression to ensure efficient disk space usage.
Compression happens inflight, i.e objects are compressed before being written to disk(s).
MinIO uses [`klauspost/compress/s2`](https://github.com/klauspost/compress/tree/master/s2)
streaming compression due to its stability and performance.

	if err != nil {
		t.Fatal(err)
	}

	for _, disk := range xl.getDisks() {
		files, _ := disk.ListDir(ctx, "", bucket, object, -1)
		for _, file := range files {
			if file != "xl.meta" {
				disk.Delete(ctx, bucket, pathJoin(object, file), DeleteOptions{
					Recursive: true,
					Immediate: false,
				})
			}
		}
	}

}

// Similar to 'len(slice)' but returns the actual elements count
// skipping the unallocated elements.
func diskCount(disks []StorageAPI) int {
	diskCount := 0
	for _, disk := range disks {
		if disk == nil {
			continue
		}
		diskCount++
	}
	return diskCount
}

// hashOrder - hashes input key to return consistent
// hashed integer slice. Returned integer order is salted

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package ioutil

import (
	"io"
	"io/fs"
	"os"

	"github.com/minio/minio/internal/disk"
)

var (
	// OpenFileDirectIO allows overriding default function.
	OpenFileDirectIO = disk.OpenFileDirectIO
	// OsOpen allows overriding default function.
	OsOpen = os.Open
	// OsOpenFile allows overriding default function.
	OsOpenFile = os.OpenFile
)

	defer updateOSMetrics(osMetricOpen, name)(err)
	return os.Open(name)
}

// OpenFileDirectIO captures time taken to call disk.OpenFileDirectIO
func OpenFileDirectIO(name string, flag int, perm os.FileMode) (f *os.File, err error) {
	defer updateOSMetrics(osMetricOpenFileDirectIO, name)(err)
	return disk.OpenFileDirectIO(name, flag, perm)
}

// Lstat captures time taken to call os.Lstat

	Exists  bool      `msg:"ex"`           // Returns whether the file existed on disk.
	Error   string    `msg:"er,omitempty"` // Returns any error when reading.
	Data    []byte    `msg:"d"`            // Contains all data of file.
	Modtime time.Time `msg:"m"`            // Modtime of file on disk.
}

// DeleteVersionHandlerParams are parameters for DeleteVersionHandler

	healSeqMap map[string]*healSequence // Indexed by endpoint
	// keep track of the healing status of disks in the memory
	//   false: the disk needs to be healed but no healing routine is started
	//    true: the disk is currently healing
	healLocalDisks map[Endpoint]bool
	healStatus     map[string]healingTracker // Indexed by disk ID
}

// newHealState - initialize global heal state management

CI=on MINIO_KMS_SECRET_KEY=minio-default-key:IyqsU3kMFloCNup4BsZtf/rmfHVcTgznO2F25CkEH1g= MINIO_ROOT_USER=minio MINIO_ROOT_PASSWORD=minio123 minio server --certs-dir /tmp/certs --address ":9002" --console-address ":11000" /tmp/minio2/{1...4}/disk{1...4} /tmp/minio2/{5...8}/disk{1...4} >/tmp/minio2_1.log 2>&1 &
echo "done"

echo -n "Starting MinIO instances ..."
minio server --certs-dir /tmp/certs --address ":9001" --console-address ":10000" /tmp/minio1/{1...4}/disk{1...4} /tmp/minio1/{5...8}/disk{1...4} >/tmp/minio1_1.log 2>&1 &
minio server --certs-dir /tmp/certs --address ":9002" --console-address ":11000" /tmp/minio2/{1...4}/disk{1...4} /tmp/minio2/{5...8}/disk{1...4} >/tmp/minio2_1.log 2>&1 &
echo "done"

if [ ! -f ./mc ]; then
	echo -n "Downloading MinIO client ..."

	// Collect any disk healing.
	healing, _ := getAggregatedBackgroundHealState(ctx, nil)
	healDisks := make(map[string]struct{}, len(healing.HealDisks))
	for _, disk := range healing.HealDisks {
		healDisks[disk] = struct{}{}
	}

	// find all disks which belong to each respective endpoints
	for i, disk := range storageInfo.Disks {
		if _, ok := healDisks[disk.Endpoint]; ok {